On the non-simultaneity of magnetic storms

Rev. Luis Rodés
1922 Journal of Geophysical Research  
in a study based chiefly on data collected by :Faris, reached the conclusion that "magnetic storms do not begin at precisely the same instant all over the Earth." The abruptly beginning ones, investigated by him, appeared to progress more often towards the east than towards the west, with a velocity such that it would require, on the average, about four minutes to encircle the Earth at the equator. • I should like to call attention to the fact that in the case of five well-defined stopms which
more » ... fined stopms which occurred subsequent to those examined by Bauer, namely, those of January, February and May, 1919, March, 1920, and May, 1921, I have found a simultaneous beginning at Tortosa and at Honolulu, which lies 158 degre. es to the west, within the limits of measurement. The photographic paper at Tortosa runs at the rate of 2.8 minutes to the millimeter and the base line is shown every hour by an electric lamp in connection with the astronomical clock, hence, I do not think we can be in error by a minute. The measures for each storm were accurately made by the writer, and the corresponding times of the beginning as registered at the other stations were kindly communicated to me by Col. E. Lester Jones, director of the U.S. Coast and Geodetic Survey, at Washington, and by Capt. R. L. Faris, acting director? Table 1 gives the times of beginning of 15 storms in comparison with the times registered at Tortosa. The storm of August 1!, 1919, began simultaneously at Lukiapang, Tortosa and Porto Rico, a range of 186 degrees in longitude, while the other stations have apparently registered it progressively earlier. The last two storms (March 22, !920, and May 13, 1921) began very suddenly and simultaneously at Tortosa, Cheltenham, Tucson, Sitka and Honolulu, represefiting aJ range of 171 degrees. •T•rr. Mag., vol. 15, 1910, pp. 221-232; R. L. F•RXS, vol. 15, I9!0, pp. 93-105; see also L..•. BAUER, vol. 15, 1910, pp. 9-20. '-I am indebted to Sir Frederic Stupart for the data of .•gincourt; to Prof. J. M. Baldwin for those of Melbourne; to 1Vlr. •V. H. Cullum for those of Tucson, and to Rev. J. de Moidre¾ for information respecting Lukiapanil. 161
doi:10.1029/te027i004p00161 fatcat:shhwpig7tndddoftyttaloigdi